DESCRIPTION

Xrandr
is used to set the size, orientation and/or reflection of
the outputs for a screen. It can also set the screen
size.

If invoked
without any option, it will dump the state of the outputs,
showing the existing modes for each of them, with a
’+’ after the preferred mode and a
’*’ after the current mode.

There are a few
global options. Other options modify the last output that is
specified in earlier parameters in the command line.
Multiple outputs may be modified at the same time by passing
multiple −−output options followed immediately
by their corresponding modifying options.

−help

Print out a summary of the usage and exit.

−v,
−−version

Print out the RandR version
reported by the X server and exit.

−−verbose

Causes xrandr to be more
verbose. When used with −q (or without other options),
xrandr will display more information about the server state.
Please note that the gamma and brightness informations are
only approximations of the complete color profile stored in
the server. When used along with options that reconfigure
the system, progress will be reported while executing the
configuration changes.

−q,
−−query

When this option is present, or
when no configuration changes are requested, xrandr will
display the current state of the system.

−−dryrun

Performs all the actions
specified except that no changes are made.

−−nograb

Apply the modifications without
grabbing the screen. It avoids to block other applications
during the update but it might also cause some applications
that detect screen resize to receive old values.

−d, −display
name

This option selects the X
display to use. Note this refers to the X screen
abstraction, not the monitor (or output).

−−screen
snum

This option selects which
screen to manipulate. Note this refers to the X screen
abstraction, not the monitor (or output).

−−q1

Forces the usage of the RandR version 1.1 protocol, even
if a higher version is available.

−−q12

Forces the usage of the RandR version 1.2 protocol, even
if the display does not report it as supported or a higher
version is available.

RandR version 1.3 options

Options for
RandR 1.3 are used as a superset of the options for RandR
1.2.
−−current

Return the current screen
configuration, without polling for hardware changes.

This option sets the panning
parameters. As soon as panning is enabled, the CRTC position
can change with every pointer move. The first four
parameters specify the total panning area, the next four the
pointer tracking area (which defaults to the same area). The
last four parameters specify the border and default to 0. A
width or height set to zero disables panning on the
according axis. You typically have to set the screen size
with --fb simultaneously.

−−transform
a,b,c,d,e,f,g,h,i

Specifies a transformation
matrix to apply on the output. Automatically a bilinear
filter is selected. The mathematical form corresponds
to:

a b c
d e f
g h i

The transformation is based on
homogeneous coordinates. The matrix multiplied by the
coordinate vector of a pixel of the output gives the
transformed coordinate vector of a pixel in the graphic
buffer. More precisely, the vector (x y) of the output pixel
is extended to 3 values (x y w), with 1 as the w coordinate
and multiplied against the matrix. The final device
coordinates of the pixel are then calculated with the
so-called homogenic division by the transformed w
coordinate. In other words, the device coordinates (x’
y’) of the transformed pixel are:

Typically, a and
e corresponds to the scaling on the X and Y axes,
c and f corresponds to the translation on
those axes, and g, h, and i are
respectively 0, 0 and 1. The matrix can also be used to
express more complex transformations such as keystone
correction, or rotation. For a rotation of an angle T, this
formula can be used:

cos T -sin T 0
sin T cos T 0
0 0 1

As a special argument, instead
of passing a matrix, one can pass the string none, in
which case the default values are used (a unit matrix
without filter).

−−scale
xxy

Changes the dimensions of the
output picture. Values superior to 1 will lead to a
compressed screen (screen dimension bigger than the
dimension of the output mode), and values below 1 leads to a
zoom in on the output. This option is actually a shortcut
version of the −−transform option.

−−primary

Set the output as primary. It
will be sorted first in Xinerama and RANDR geometry
requests.

RandR version 1.2 options

These options
are only available for X server supporting RandR version 1.2
or newer.
−−prop, −−properties

This option causes xrandr to
display the contents of properties for each output.
−−verbose also enables −−prop.

−−fb
widthxheight

Reconfigures the screen to the
specified size. All configured monitors must fit within this
size. When this option is not provided, xrandr computes the
smallest screen size that will hold the set of configured
outputs; this option provides a way to override that
behaviour.

−−fbmm
widthxheight

Sets the reported values for
the physical size of the screen. Normally, xrandr resets the
reported physical size values to keep the DPI constant. This
overrides that computation.

−−dpi
dpi

This also sets the reported
physical size values of the screen, it uses the specified
DPI value to compute an appropriate physical size using
whatever pixel size will be set.

−−newmode name
mode

New modelines can be added to
the server and then associated with outputs. This option
does the former. The mode is specified using the
ModeLine syntax for xorg.conf: clock hdisp hsyncstart
hsyncend htotal vdisp vsyncstart vsyncend vtotal
flags. flags can be zero or more of +HSync,
-HSync, +VSync, -VSync, Interlace, DoubleScan, CSync,
+CSync, -CSync. Several tools permit to compute the usual
modeline from a height, width, and refresh rate, for
instance you can use cvt.

−−rmmode
name

This removes a mode from the
server if it is otherwise unused.

−−addmode output
name

Add a mode to the set of valid
modes for an output.

−−delmode output
name

Remove a mode from the set of
valid modes for an output.

Per-output
options
−−output output

Selects an output to
reconfigure. Use either the name of the output or the
XID.

−−auto

For connected but disabled outputs, this will enable
them using their preferred mode (or, something close to
96dpi if they have no preferred mode). For disconnected but
enabled outputs, this will disable them.

−−mode
mode

This selects a mode. Use either
the name or the XID for mode

−−preferred

This selects the same mode as
−−auto, but it doesn’t automatically
enable or disable the output.

−−pos
xxy

Position the output within the
screen using pixel coordinates. In case reflection or
rotation is applied, the translation is applied after the
effects.

−−rate
rate

This marks a preference for
refresh rates close to the specified value, when multiple
modes have the same name, this will select the one with the
nearest refresh rate.

−−reflect
reflection

Reflection can be one of
’normal’ ’x’, ’y’ or
’xy’. This causes the output contents to be
reflected across the specified axes.

−−rotate
rotation

Rotation can be one of
’normal’, ’left’,
’right’ or ’inverted’. This causes
the output contents to be rotated in the specified
direction. ’right’ specifies a clockwise
rotation of the picture and ’left’ specifies a
counter-clockwise rotation.

−−left−of,
−−right−of, −−above,
−−below, −−same-as
another-output

Use one of these options to
position the output relative to the position of another
output. This allows convenient tiling of outputs within the
screen. The position is always computed relative to the new
position of the other output, so it is not valid to say
−−output a −−left−of b
−−output b −−left−of a.

−−set property
value

Sets an output property.
Integer properties may be specified as a valid (see
−−prop) decimal or hexadecimal (with a leading
0x) value. Atom properties may be set to any of the valid
atoms (see −−prop). String properties may be set
to any value.

−−off

Disables the output.

−−crtc
crtc

Uses the specified crtc (either
as an index in the list of CRTCs or XID). In normal usage,
this option is not required as xrandr tries to make sensible
choices about which crtc to use with each output. When that
fails for some reason, this option can override the normal
selection.

−−gamma
red:green:blue

Set the specified floating
point values as gamma correction on the crtc currently
attached to this output. Note that you cannot get two
different values for cloned outputs (i.e.: which share the
same crtc) and that switching an output to another crtc
doesn’t change the crtc gamma corrections at all.

−−brightness
brightness

Multiply the gamma values on
the crtc currently attached to the output to specified
floating value. Useful for overly bright or overly dim
outputs. However, this is a software only modification, if
your hardware has support to actually change the brightness,
you will probably prefer to use xbacklight.

RandR version 1.1 options

These options
are available for X servers supporting RandR version 1.1 or
older. They are still valid for newer X servers, but they
don’t interact sensibly with version 1.2 options on
the same command line.
−s, −−size size-index or
−−size widthxheight

This sets the screen size,
either matching by size or using the index into the list of
available sizes.

−r, −−rate,
−−refresh rate

This sets the refresh rate
closest to the specified value.

−o,
−−orientation rotation

This specifies the orientation
of the screen, and can be one of normal, inverted, left or
right.

−x

Reflect across the X axis.

−y

Reflect across the Y axis.

EXAMPLES

Sets an output
called LVDS to its preferred mode, and on its right put an
output called VGA to preferred mode of a screen which has
been physically rotated clockwise: